In general, a motor transmits a rotating force of a rotor to a rotating shaft which drives a load. For example, the rotating shaft of the motor can drive a drum of a washing machine connected thereto, or a fan of a refrigerator connected thereto for supplying cold air to a required space.
Recently, a BLDC (brushless direct current) motor has been widely used since it has no brush to cause almost suppression of noise and to provide extended life span. The rotor in the BLDC motor becomes rotated through an electromagnetic interaction with a stator. So as to perform the electromagnetic interaction, coils, which are made of a material like copper or aluminum, are wound on the stator, and as electric current is applied to the coils, the rotor rotates with respect to the stator.
On the other hand, insulators are used to insulate the coils wound on the stator from the stator core. Generally, the insulator of conventional motors largely includes an upper insulator and a lower insulator made through plastic injection molding, wherein the upper insulator and the lower insulator are assembled to each other as one unit in such a manner as to completely cover the stator core.
By the way, in case where the upper insulator and the lower insulator are made through the plastic injection molding, the stacked heights of the stator core may be varied, and in this case, the molds for molding the upper insulator and the lower insulator are separately manufactured in accordance with the varied heights of the stator core.
Further, since the upper insulator and the lower insulator are plastic injection-molded materials, they have a predetermined thickness so that the spaces, that is, the slots, between teeth of the stator core become narrow to cause the spaces in which the coils are wound to be reduced.
Moreover, since the upper insulator and the lower insulator are formed to cover the entire teeth of the stator core, a quantity of the plastic material used becomes increased.